Pathogenesis of Nerve Injury: Role of Tissue Inhibitor of Metalloproteinases-1 (TIMP-1)

四肢创伤导致的周围神经系统(PNS)损伤占战伤的大部分。 尽管三叉神经节具有很高的再生能力，但患者会出现严重的神经病理性疼痛，不符合 止痛疗法。2017年国会阿片类药物和停止倡议法案呼吁“扩大、强化和 协调基础研究、翻译研究和临床研究 关于疼痛和发展新的非成瘾性疼痛 治疗。 除了身体和精神上的残疾，慢性疼痛还给美国造成了超过美元的损失 每年6000亿美元 年。超过65%的美国退伍军人报告疼痛，退伍军人的剧烈疼痛比非退伍军人高40% 退伍军人。 我们的无偏转录组学研究发现金属蛋白酶组织抑制因子-1(TIMP-1)在 在痛性三叉神经节损伤中，前10位基因被诱导(在数千个调控基因中)。TIMP-1的主要功能是 抑制细胞外基质金属蛋白酶(MMPs)家族。在该退伍军人事务部的框架内 MERIT计划，我们率先研究了MMPTIMP轴在三叉神经节损伤和疼痛调节中的作用。这 更新应用的中心是我们的第二个公正的发现：TIMP-1是一个X染色体连锁的基因， 在疼痛的三叉神经节损伤中表现出多态、异常和性别依赖的转录异构体。 我们的数据有力地表明TIMP-1是一种在PNS中诱导的镇痛、促进生存和再生的因子。 作为对受伤的反应。然而，多态、异常的TIMP-1转录本变体的表达可能 导致功能失调的基因或蛋白质产物，容易导致慢性疼痛的发展。带着我们的 创新的工具和概念，突破性的数据和在MMP/TIMP和PNS研究方面的良好记录， 我们的目标是研究细胞和亚细胞，包括TIMP-1分布的核模式，相互作用和 在三叉神经节损伤中的作用(目标1)。然后我们将鉴定TIMP-1基因的性别特异性、异常、转录本变体 由于性二型(女性X染色体失活)和单形性(在两者中普遍存在)引起的 性别)表观遗传异常(目标2)。由于人类体内存在TIMP-1基因的多态变异，我们希望我们的 这些发现将迅速转化为临床环境中疼痛状态的医学表观遗传学诊断。最后我们 目的建立靶向TIMP-1基因治疗三叉神经节损伤和疼痛(AIM 3)。 该计划采用了多学科最先进的技术(如RNA-SEQ、SMRT-BS、BioID、芯片) 以及研究三叉神经节损伤和疼痛的基本神经病理学和行为方法。我们期待着 我们的计划将对疼痛诊断和非成瘾性止痛药的开发产生重大影响。

Extremity trauma causing peripheral nervous system (PNS) injury accounts for the majority of combat wounds. Despite high regenerative capacity of the PNS, patients develop severe neuropathic pain, not amenable to analgesic therapies. The congressional Opioids and STOP Initiative Act of 2017 calls to “expand, intensify, and coordinate fundamental, translational, and clinical research” on pain and develop new non-addictive pain treatments. In addition to physical and emotional disability, chronic pain costs the U.S. over $ 600 billion every year. Over 65% of American Veterans report pain, with severe pain 40% greater in Veterans than non- Veterans. Our unbiased transcriptomics study identified Tissue Inhibitor of Metalloproteinases-1 (TIMP-1) among the top-10 induced (out of thousands regulated) genes in painful PNS injury. The main function of TIMP-1 is inhibition of the matrix metalloproteinase (MMP) family of extracellular proteases. In the framework of this VA Merit program, we have pioneered the study of the MMP/TIMP axis in PNS injury and pain regulation. This renewal application centers on our second unbiased finding: TIMP-1 is an X-chromosome-linked gene, exhibiting polymorphic, aberrant and sex-dependent transcript isoforms in painful PNS injury. Our data strongly suggest that TIMP-1 is an analgesic, pro-survival and regenerative factor induced in the PNS in response to injury. However, expression of polymorphic, aberrant TIMP-1 transcript variants, potentially resulting in dysfunctional gene or protein products, predisposes to chronic pain development. With our innovative tools and concepts, groundbreaking data and strong track record in MMP/TIMP and PNS research, we aim to study cellular and subcellular, including nuclear patterns of TIMP-1 distribution, interactors and functions in PNS injury (Aim 1). We will then identify sex-specific, aberrant, transcript variants of TIMP-1 gene arising due to sexually dimorphic (X chromosome inactivation in females) and monomorphic (universal in both sexes) epigenetic abnormalities (Aim 2). As polymorphic TIMP-1 variants occur in humans, we expect our findings will swiftly translate into medical epigenetic diagnostics of pain states in a clinical setting. Finally we aim to develop targeted TIMP-1 gene therapy in PNS injury and pain (Aim 3). This program employs multidisciplinary state-of-the-art (e.g. RNA-seq, SMRT-BS, BioID, ChiP) technologies and fundamental neuropathological and behavioral approaches to study PNS injury and pain. We anticipate our program will make a major impact on pain diagnostics and development of non-addictive analgesics.